Advances in technology have provided for growth in the electronic industry. In order to meet the world's growing demands for electronics, millions of semiconductor devices are needed. Semiconductor devices are usually created from dies cut from a single processed substrate.
To process a substrate, a gas mixture (e.g., etchant gas mixture) may flow into a processing chamber and be energized by radio frequency (RF) power to form an ion energy cloud (i.e., plasma). Plasma may then be employed to etch the substrate to form semiconductor devices. In many cases, it has been found that the etch rate may be higher at the edge of the substrate. It is theorized that since less substrate surface area at the substrate edge is available to be etched for a given volume of etchant, the edge of the substrate usually experiences a higher etch rate, thereby resulting in substrate non-uniformity.
As aforementioned, since more etchant is available at the edge of the substrate than at the center, the plasma formed over the substrate may be non-uniform. Since plasma uniformity is desired during substrate processing to ensure a consistent etch rate across the substrate in order to reduce the potential of creating defective semiconductor devices, most substrate processing has been focused toward the bulk area of the substrate (i.e., the area away from the edge of the substrate) where plasma uniformity has been more consistently observed. As a result, areas around the edge of a substrate have been discarded as some manufacturers considered this waste as a cost of manufacturing.
In today competitive market, processing substrates into quality semiconductor devices while minimizing waste may give a manufacturer a competitive edge. One way to reduce waste is to maximize the real estate surface of the substrate being processed and utilize as much of this real estate as possible to produce quality semiconductor devices. The ability to maximize utilization of the real estate surface of the substrate while minimizing the number of defective semiconductor devices is especially advantageous for manufacturers that utilize plasma processing systems capable of processing large substrates.
Generally speaking, by employing a processing system capable of processing large substrates, a higher number of semiconductor devices may be created per unit of machine run time in comparison to a processing system that is capable of processing substrates of smaller sizes. However, if a manufacturer is unable to process the area around the edge of a large-sized substrate to create acceptable semiconductor devices, the revenue lost experienced by the manufacturer may be high given that a large-sized substrate tends to have a larger diameter and thus a larger periphery area.
Thus, an arrangement for manipulating plasma confinement to improve substrate processing at the edge of a substrate is desired.